New Astrobites Post: A Binary Jupiter Trojan Reveals the Solar System's Early History

In this post, I reviewed a paper that studied a peculiar binary asteroid system
called (617) Patroclus-Menoetius that orbit around the Sun in a similar path as
Jupiter (just 60 degrees behind Jupiter in its orbit). Binary systems contain two similarly-sized
objects in orbit around a mutual center of mass (think more along the lines of
Pluto and Charon, rather than the Earth and Moon). Binary asteroids are
interesting because they’re likely some of the oldest relics in the Solar
System. They probably formed when the cloud of “pebbles” that comprised the early
planetesimal disk was still condensing and could easily form pairs of
objects. Over time, though, encounters with other objects (like other asteroids
or big planets) can disrupt binaries, causing them to collide or drift
apart. The fact that Patroclus-Menoetius has survived the entirety of the Solar
System’s lifetime can put some strong constraints on possible events in the
Solar System’s history that would have otherwise disrupted the pair. The authors
of the paper ran simulations of the early Solar System to figure out the
conditions in which a binary pair like Patroclus-Menoetius could survive.

I won’t spoil the answer here, you’ll just have to go read the post! But what’s
especially exciting is that NASA’s Lucy
mission,
due to launch in 2021, will
visit this curious binary system in 2033. So we’ll soon know even more about
this system and be able to place even stronger constraints on conditions in the
early Solar System!